22i} 



multiplication of the rat-flea may be controlled or checked, or the 

 number reduced that each rat is able to harbour. It is considered 

 that the use of tobacco in some form might be well worth consideration 

 in this connection. 



White (Major F. N.). Plague and Rat Destruction. — Indian Med. 

 Gaz., Calcutta, liii, no. 8, August 1918, pp. 281-284. 



This paper criticises severely the views advanced in the preceding 

 one. The chief points of Col. Deimys' argument are enumerated 

 and are met with the assertion that " every single one of these state- 

 ments is incorrect in the context in which it is placed and the vast 

 majority of them are absolutely and fundamentally wrong." It is 

 pointed out that there is no season in any part of India where Xeno- 

 psylla cheopis (rat-flea) is " conspicuous by its absence," and figures 

 are quoted giving the average number of fleas per rat in various parts 

 of India where well-marked epidemics of plague occur. These figures 

 are considered as sufficient refutation of the theory that where chronic 

 flea- infestation is found plague becomes endemic, and where there is 

 seasonal infestation, epidemic plague occurs. The statement that the 

 eggs of fleas laid in one spring hatch in the following spring, while 

 not true even in the low temperatures of England, can certainly not 

 be applied to any locality in plague-infected India. In the Bombay 

 Presidency and in the Punjab, for instance, Xenopsylla cheopis lays 

 eggs at all seasons of the year ; these hatch in a few days, in Bombay 

 in about two days. The author remarks that all who have given 

 any time to the study of X. cheopis vnW ap^jreciate the fact that the 

 only practical way of dealing efltectively with that parasite is by 

 attacks on the rat, its definitive host, a proceeding that Colonel 

 Dennys stigmatises as useless and dangerous. It is pointed out that 

 the extent to wliich previous scientific work on the subject is ignored 

 by Colonel Dennys makes it extremely difficult to frame a conclusive 

 reply to his arguments. Many important results, a few of which 

 are summarised in this paper, have been obtained by observations 

 on thousands of rats and fleas carried on over a period of several 

 years. While this work is ignored by Colonel Deimys, not a single 

 fact is deduced to support his original ideas about the epidemiology 

 of plague. 



Criticising the second of the papers reviewed above, the author 

 maintains that the information given is not nearly sufficient to enable 

 the reader to draw any such conclusions as are deduced therefrom. 

 While admitting that indiscriminate rat destruction, as it is too often 

 carried out, effects very little good and frequently ends in failures 

 such as those enumerated by Colonel Dennys, the conclusion arrived 

 at is that the methods employed were ineffective, and not that rat 

 destruction in itself is a harmful measure. The author concludes 

 the present paper with his own views upon the measures to be taken 

 in a plague-infested town, and the best method of conducting an 

 anti-rat campaign. To start rat destruction measures only after an 

 epizootic has started, and to give them up directly the epidemic begins 

 to decline, naturally leads to disbelief in rat-extermmation measures. 

 The present attempts to increase the efficacy of rat-destruction methods 



